Condenser



July 20 1926.

G. W. LILIENTHAL- CONDENSER Filed April 21, 1925 INVENTOR Patented July20, 1926 UNITED "STATES PATENT OFFICE.

GEORGE W. LILIEN THAL, OF NEW YORK, N. Y., .ASSIGNOR TO WIRELESS RADIOCOR- PORATION, OF- NEW YORK, N. Y.,

A CORPORATION OF NEW YORK.

CONDENSER.

Application filed August 21, 1925. SerialNo. 51,550.

This invention relates toielectrical condensers: of adjustableicapacityadapted to be used in radio transmitting andreceiving circuits and forother-electrical apparatus.

An object of the invention is to generally improve this type of deviceand to provide a condenser o'j thecharacter described of"low-loss,compact construction, and which shall be adjusta lefor low minimunrcapacity and adapted to give various deisirable capacity characteristicssuch as sub- 'stantially straight line plotted relation of the frequencyor wave length to the dial setting, etc.

A'turther object otthe invention is the provision of an improvedcondenser of the character" described comprising few and simple parts,-which is neat in appearance, rugged in construction, comparatively cheapto manufacture, and practical "and eflicient in operation to a highdegree.

Other objects of this invention will in part beobvious and in parthereinafter pointed out. I

The invention accordingly consists in the "features of construction,combinations of elements and arrangement-of parts which will beexemplified in the construction h'ereinatter described, andof'which thescope'of application will be indicatedinthe following claims.

In the'accompanying drawing,in whichv is shown one of the variouspossible illustrative embodin'ients of this invention,

Fig. 1 is a front elevational view of a con denser embodying theinvention;

Figs. 2 and 3 are planand sideelevational 1 views, respectively, otthecondenser shown in Fi 1;

Fig. i is a c-ross sectional view showing the construction of thepivoting axis of'the movable" electrode; and

Fig. 5' isan enlarged fragmentarycrosssectional view showing the sleevebearing construction=-tor=the shaft of the movable electrode.

Referring in detail to the drawing, 10

denotes a condenser-embodying the inven-r de'slgned to have substantion, preferably tially straight line character stics, that 1s,

the various signalirequencies when plotted relative to the graduationson the control dial *(notshown) gives substantially a straight line.structed with relatively little insulating material and has its parts sodisposedas to The condenser 10 is conreduce the electrical losses to apractical minimum thus forming a so-called low loss condenser.

As seen from the drawing, the condenser 10 comprises a front mountingplate '11 supporting a pair of spaced, rearwardly extending stanchions12and 13 having threadmembcrs l2 and 13, respectively, screwed into theends thereof, a nut 14: being carried on each member to loclr the latterin an adjusted posit-ion to said stanchions' for the purpose that willhereinafter appear.

'Said stanchions 12, 13 are insulated: from the plate 11 by suitablemeans such as the interposed bases 15 made of bakelite or other likematerial, the stanchions being secured to said base by means of screws16,

and the bases to said plate 11 bymeans of screws 17 as shown in Figs. 1and 3.

Upon said threaded members 12 and 13 are mounted fined condenser plates;18;and

washers 19 of uniform thickness are provided to insure a desiredaccuratespacing. Screwed on saidmembers 12 and 13 are clamping nuts 20which serve to hold the fixed plate 18 in alignment and secure saidplates and washers together to form the 1 stationary electrode or-statorof the condenser 10 as shown in Fig. 2.

Movable condenser plates 21y63,(3l1- S8p arated by: a washer- 22 arerigidly fastened in :uniformlyspaced relation on a shaft .43 and arerotatably mo unted for movement in and out between the fixed plates 18to form the adjustable condenser electrode or rotor. The shaft 23 isjournaled in a single sleeve bearing 2 1 which preferably is rigidlysecured so as to extend rearwardly from the plate 11 by means of ariveted overturned connection 25 (see Fig. 5).

The' end of the rear portion 23* oi the shaft 23 supporting the plates21 may be threaded to receive a nut 26 which is adapted to clamp theplates 21 and washers 22 in position against a shouldered enlargement 23of the'shaft- 23- and preferably LEOllHQfl integral therewith at themid-portion thereof as shown in Fig. 4;.

To'elin'iinate accidental transverse or side displacement of the movableplates 21 with respect to the stationary plates 18, there is provided onthe shoulder of the front end of said enlarged portion 23 of said shafta bevelled or tapering bearing surface 23 adapted to co-operate with acorrespondingly dished surface 2%. on the rear end of the bearing 24:,and a collar nut 27 having a bevelled leading end 2T screwed to theshaft for engaging with the dished surface as on the front end of saidhearing as shown in Fig. 4;. The shaft 23 is thus positively heldagainst lateral. shifting in the bearing 24:, and said collar-nutprovides means for adjusting the friction between said surfaces forretaining the shaft 23 and movable plates 21 in any set position withrespect to the stationary plates 18. Suitable means such as a loclc nut28 screwed against the collar nut 2'? may be provided for securing thelatter against movement from an adjusted position.

As seen from Fig. 1, the movable plates 21 are preferably of properasynnnetrically curved shape to give substantially straight line plottedrelation of the frequency of the signal with respect to the angulardisplacement of the adjustable electrode with rela tion to thestationary electrode, the degree of said angular displacementcorresponding directly to the graduation on the control dial, as is wellunderstood.

One end of each of said plates 21 is secured to the shaft 23 the otherends thereof being provider, with extending portions 21 having a throughbolt 29 and separating washers 30 to more firmly hold the plateuniformly spaced and to increase the rigid ity of the movable electrode.(See F igs. 2 and 3.)

To prevent the movable electrode from forming a metallic contact withthe stationary one in its extreme swung positions, insulating washers 31and 32 are provided, one or more washers 3]. being mounted on the member12 between the fixed plates 18 as for example, one adjacent each of therear and front plates 18 and 18 respectively, and one or more washers 82being mounted on the bolt 29 as for example one on each end against theexterior sides of the movable electrodes as shown in Fig. 3.

By making the washers 31 and 32 larger in diameter than the spacingwashers 19 and 30 respectively, the former serve stops to hold theelectrodes against coming in metallic contact with each other and alsolimit the relative swinging movementof said electrodes.

Suitable terminal pieces 83 and 3st for connecting the condenser into acircuit are provided. the terminal piece 33 being secured to themounting plate 11 in any suitable manner as by means of screw 17 forconnecting with the movable electrode through the bearing 2% and shaft23, while the terminal piece 30 is mounted on the member 13 against thestationary electrode as shown in Fig. 2.

A spring washer jumper 35 frictionally engaging the collar nut 27 andcontacting with the plate 11 provides a secondary path or shunt circuitfor the current from the plate 11 to the movable electrode supplementingthe circuit formed by the sleeve 24 with the shaft 28 as shown in Figs.1 and 5.

Suitable means for mounting the con denser 10 to a support (not shown)may be provided such as a pin 'ality of spacing members 36 secured toextend from the front of plate 11. Said members may be threaded as at 3?for receiving fastening screws (not shown).

To assemble the condenser 10 is a comparati'vely simple matter. First,the plates 19 are mounted on members 12 and 13 in spaced relation toform the fixed electrode, and then the latter is properly aligned withrespect to the spaced movable plates 21 which are assembled on the shaft23 and journaled in the bearing 24 by adjusting and locking said memberson their respective stanchions 12 and 13 as shown in Figs. 2 and 8.

It will thus be seen that there is pro vided a device in which theseveral objects of this invention are achieved, and which is welladapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention,and as various changes might be made in the embodiment above set forth,it is to be understood that all matter herein set forth or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimit ing sense.

Having thus described my invention, I claim as new and desire to secureby Letters Patent 1. A condenser comprising a front mount-- ing plate, apair of spaced stanchions sup ported on said plate, each stanchionhaving a threaded member screwed into the end thereof, a base insulatingeach stanchion from the plate, an electrode mounted on said members toform the stator of the condenser, a single sleeve bearing secured tosaid plate, a shaft journaled in said bearing, and an electrode securedto the shaft to form the rotor of the condenser, said stanchions andmembers being adjustable to permit aligning of the rotor and stator inproper co-- operative relation.

2. A condenser comprisingafront mounting plate, a pair of spacedstanchions sup ported on said plate, each stanchion having a threadedmember screwed into the end thereof, a base insulating each stanchionfrom the plate, an electrode mounted on said members to form the statorof the condenser,

a single sleeve bearing secured to said plate, a shaft journaled in saidbearing, and an electrode secured to the shaft to form the rotor of thecondenser, said stanchions and members being adjustable to permitaligning of the rotor and stator in proper cooperative relation, andmeans mounted on the member engaging each stanchion to lock the memberin the adjusted position.

3. A condenser comprising a front mounting plate, a pair of spacedstanchions supported on said plate, each stanchion having a threadedmember screwed into the end thereof, a base insulating each stanchionfrom the plate, an electrode mounted on said members to form the statorof the condenser, a single sleeve bearing secured to said plate, a shaftjournaled in said bearing, an electrode secured to the shaft to form therotor of thecondenser, said stanchions and members being adjustable topermit aligning of the rotor and stator in proper cooperative relation,a terminal piece secured to the plate connecting with the rotor throughsaid bearing and shaft, and a spring jumper secured between said plateand said shaft to form a shunt circuit about said bearing. a

l. A condenser comprising a front mounting plate, a pair of spacedstanchions supported on said plate, each stanchion having a threadedmember screwed into the end thereof, a base insulating each stanchionfrom the plate, a metallic electrode mounted on said members to form thestator of the condenser, a single sleeve bearing secured to said plate,a shaft journaled in said bearing, and a metallic electrode secured byone end thereof to said shaft to form the rotor of the condenser, saidstanchions and members being adjustable to permit aligning of the rotorand stator in proper co-operative relation, the other end of theelectrode and one of said members each having means for preventing therotor and stator from coming into metallic contact.

5. A condenser comprising a mounting plate, a plurality of metallicplates supported and insulated from said plate secured together inuniform spaced relation adapted to form the stator electrode, a singlebearing rigidly secured to said plate, a shaft journaled in saidbearing, a plurality of metallic plates secured together in uniformspaced relation adapted to form the rotor electrode and mounted by oneend thereof to said shaft, said stator being adjustably support ed bythe mounting plate to permit aligning the stator and rotor inproperco-operative relation, and an insulating member forming part of eachelectrode for preventing the rotor and stator from coming into metalliccontact and serving as stops to limit the movement of the rotor.

6. A condenser comprising a mounting plate, a plurality of metallicplates supported and insulated from said plate secured together inuniform spaced relation adapted to form the stator electrode, a singlebearing rigidly secured to said plate, a shaft journaled in saidbearing, a plurality of metallic plates secured together in uniformspaced relation adapted to form the rotor electrode and mounted by oneend thereof to said shaft, the ends of the plates of the other end ofthe electrode having extensions, means projecting through said portionsfor spacing and securing said rotor plate ends together to increase therigidity of the rotor, and insulating members carried by said means andby the stator electrode to provide stops to prevent the electrodes frommaking metallic contact with each other.

In testimony whereof I affix my signature.

GEORGE W. LILIENTHAL.

